The proposal has two specific aims: 1) to determine the extent to which baroreceptor denervation alters the renal response to volume expansion, head-out water immersion, and selective atrial distension in the primate. In addition, data will be obtained concerning the extent to which baroreceptor denervation may produce a hypertensive state, and 2) to determine if afferent neural activity from the kidney and liver can appraise the central nervous system of the composition and volume of blood which perfuses these organs. These proposals relate directly to understanding better salt and water homeostasis in man. Standard physiological methodology will be employed.